DESTRUCTIVE INSECTS. 161 



bristles which are worked along a groove in a supporting beak 

 or elongated lower lip. These insects place the point of this 

 beak on the surface of the plant, force the bristles into the 

 tissue, and then, by the help of a muscular box in the throat, 

 they draw or suck up along the beak the liquid juices from 

 the interior of the plant. 



One can readily see how the biting or chewing insects are 

 killed by putting a poisonous powder or spray on the surface 

 of the plant attacked; particles of the poison would be taken 

 into the body with the solid food in eating. But a sucking in- 

 sect can eat only liquid food, which it gets from the interior 

 of the plant; hence it could not eat a poison put upon the 

 surface. And as it is not possible to poison the internal tis- 

 sues or juices, one is forced to use something besides poisons 

 to kill sucking insects. They can be killed by suffocating 

 them with a gas, like hydrocyanic acid gas, or with a powder, 

 like pyrethrum, which stops up their breathing-holes, or with 

 some liquid, like kerosene or a soap solution, which kills by 

 soaking into their body or in the same way as the powders. 

 Many pounds of Paris green have been wasted in trying to 

 feed it to sucking insects. 



Fruit-growers can readily determine if an insect is chewing 

 or sucking its food. If of the former class, then aim a poison 

 spray at the part of the plant where it is feeding; but if it is 

 a sucking insect, then aim an oil or soap spray at the insect 

 itself. 



There are a hundred or more different kinds of injurious 

 insects, and equally as many diseases, which sometimes seri- 

 ously interfere with the growing of a profitable crop of fruit. 

 Most of the serious or standard insect pests and the more 

 common diseases which are met with by the fruit-grower will 

 be found treated of in this chapter; the others which occur 

 less frequently, or become serious in their effects in restricted 

 localities, it has not been considered necessary to treat of here. 

 In all such cases advice should immediately be sought from 

 the State Agricultural Experiment Station. (For list see chap- 

 ter xvi.) 



In previous editions of this work no logical plan was fol- 

 lowed in discussing the destructive insects. We have thought 

 it advisable to change this and first discuss the apple pests, 



